C 1500 Truck 2WD V8-5.3L VIN T (1999)
PROM - Programmable Read Only Memory: Customer Interest
A/T - Harsh 1-2 and 3-2 Shifts
File In Section: 07 - Transmission/Transaxle
Bulletin No.: 99-07-30-009
Date: June, 1999
TECHNICAL
Subject:
Harsh 1-2 and 3-2 Shifts (Reprogram PCM)
Models:
1999 Chevrolet and GMC C/K Models (Silverado and Sierra) with 4.8 L or 5.3 L Engine (VINs V, T - RPOs LR4, LM7) and Hydra-Matic 4L60-E
Transmission (RPO M30)
Condition
Some customers may comment about a harsh 1-2 upshift during acceleration at light to moderate throttle opening. It is characterized by a "Bump" at the
end of the shift. A similar condition may exist during a "Power-on" 3-2 downshift.
Cause
Condition may be caused by insufficient line pressure to complete the shift caused by component variation.
Correction
Reprogram the Powertrain Control Module (PCM) with the calibrations listed in this bulletin.
Parts Information
The calibrations listed are electronic calibrations and are NOT available from GMSPO. Calibrations will be available from Techline starting April 1999,
on the 1999 Disk 10 CD ROM.
Warranty Information
For vehicles repaired under warranty, use:
Labor
Operation
Labor Description
Labor Time
PROM
Use Published
J6355
Reprogramming
Labor Time
